package endpoints

import (
	"arbeitszeitmessung/helper"
	"arbeitszeitmessung/models"
	"arbeitszeitmessung/templates"
	"encoding/json"
	"log"
	"net/http"
	"strconv"
	"time"
)

// Frontend relevant backend functionality -> not used by the arduino devices
func TimeHandler(w http.ResponseWriter, r *http.Request) {
	helper.SetCors(w)
	switch r.Method {
	case "GET":
		getBookings(w, r)
	case "POST":
		updateBooking(w, r)
	case "OPTIONS":
		// just support options header for non GET Requests from SWAGGER
		w.WriteHeader(http.StatusOK)
	default:
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
	}
}

func parseTimestamp(r *http.Request , get_key string, fallback string) (time.Time, error) {
	_timestamp_get := r.URL.Query().Get(get_key)
	if(_timestamp_get == "") {
		_timestamp_get = fallback
	}
	timestamp_get, err := time.Parse("2006-01-02", _timestamp_get)
	if(err != nil){
		return time.Now(), err
	}
	return timestamp_get, nil
}


// Returns bookings from DB with similar card uid -> checks for card uid in http query params
func getBookings(w http.ResponseWriter, r *http.Request) {
	card_uid := r.URL.Query().Get("card_uid")
	if card_uid == "" && Session.Exists(r.Context(), "card_uid"){
		card_uid = Session.GetString(r.Context(), "user")
	}
	if card_uid == "" {
		http.Error(w, "Missing card_uid query parameter", http.StatusBadRequest)
		return
	}

	tsFrom, err := parseTimestamp(r, "time_from", "2000-01-01")
	if(err != nil ){
		log.Println("Error parsing 'from' time", err)
		http.Error(w, "Timestamp 'from' cannot be parsed!", http.StatusBadRequest)
		return
	}
	tsTo, err := parseTimestamp(r, "time_to", time.Now().Format("2006-01-02"))
	if(err != nil ){
		log.Println("Error parsing 'to' time", err)
		http.Error(w, "Timestamp 'to' cannot be parsed!", http.StatusBadRequest)
		return
	}
	tsTo = tsTo.AddDate(0,0,1) // so that today is inside

	bookings, err := (*models.Booking).GetBookingsGrouped(nil, card_uid, tsFrom, tsTo)
	if err != nil {
		log.Println("Error getting bookings: ", err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}
	templates.OverviewPage(bookings).Render(r.Context(), w)
	// w.Header().Set("Content-Type", "application/json")
	// json.NewEncoder(w).Encode(bookings)
}

// Updates a booking form the given json body
func updateBooking(w http.ResponseWriter, r *http.Request) {
	_booking_id := r.URL.Query().Get("counter_id")
	if _booking_id == "" {
		http.Error(w, "Missing bookingID query parameter", http.StatusBadRequest)
		return
	}
	booking_id, err := strconv.Atoi(_booking_id)
	if err != nil {
		http.Error(w, "Invalid bookingID query parameter", http.StatusBadRequest)
		return
	}
	bookingDB, err := (*models.Booking).GetBookingById(nil, booking_id)
	if err != nil {
		log.Println("Error getting booking: ", err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}
	var booking models.Booking
	dec := json.NewDecoder(r.Body)
	dec.DisallowUnknownFields()
	err = dec.Decode(&booking)
	if err != nil {
		log.Println("Error parsing booking: ", err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}
	if booking.CounterId != 0 && booking.CounterId != bookingDB.CounterId {
		log.Println("Booking Ids do not match")
		http.Error(w, "Booking Ids do not match", http.StatusBadRequest)
		return
	}
	bookingDB.Update(booking)
	bookingDB.Save()
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(bookingDB)
}